Hydraulic tractor drawbar pounds pull tester



`lune 2, 1953 C, Q HEFNER 2,640,353

HYDRAULIC TRACTOR DRAWBAR POUNDS PULL TESTER Filed Sept. 18, 1950JNVENTOR. 6'0/1//27 Q Hef Patented June 2, 1953 UNITED STAT-ESS OFFICEHY'DRAULI'C TRACTOR yI)RAXZV'BAR "POUND S PULL TESTER Calvin Q; Hefner,Sublette, Kans.

Application September 18, 1950, Serial No. 185,459

(Cl. F13-141;)

42 Claims. 1

This invention relates to the art of force measurement and has for itsprimary Laim the provision of lan instrument designed particularly forinterposition ybetween a tow-ing device, such as .a .tractor or thelike, and a towed implement `of vany form, which instrument indicatesAto the operator the number of pounds .pull being exerted.

Oneotthe primary aims of `this invention is to provide an hydrauliclpounds pull .tester yof the aforementioned .generalcharacter and whichis particularly designed to beflposi-tioned between -a tractor and theload being` drawn thereby, where- .jby the operator mayquickly andaccurately determine the force being exerted iny the tow-ing Loperationand learn from time to .time the .pre-

cise number .of `pounds pull .being exerted.

A still fruther .aim of this invention is the provision `o1 vanhydraulic pounds pull indicating instrument which is effective vwhenforming a part of the drawbar assembly of -a tractor and that willpermit the operator to test both the action of the tractor andresistance ofthe load being towed thereby without the employment vofexpensive, complicated .and involved apparatus which otherwise mighteiiect the normal function of the tractor and its load.

Additional and important `objects of this in- `vention are to provide apounds pull tester of the aforementioned general form and character andwhich is relatively inexpensive to produce, will not become maladjustedduring normal employment and that may be interposed between a pullingtractor and its load with speed land assurance that 'the resultsindicated by the` gauge forming a `part of the instrument will beaccurate.

Details of construction are important and such objects of the inventionas are embodied therein will appear during the course of the followingspeciication, referring to accompanying drawing, wherein:

Fig. 1 is a side elevational view of an hydraulic tractor drawbar'pounds pull tester made in accordance with this invention.

Fig. 2 is a top plan View of the said pounds pull tester per se.

Fig. 3 is a fragmentary, side elevational View with parts broken away torevealthexnature and disposition of the gauge-actuating cylinder andplunger'.

Fig. 4 is a cross sectional view taken `on line IV-IV of Fig. 3; and,

Fig. 5 is a cross sectional view taken on line V--V 0f Fig. 3.

In the normal operation of 'the instrument, the Asame is interposedbetween the drawbar 'l 'of an ordinary tractor (not here shown) and thework I2 to which force is being applied 'by said tractor. The force isexerting a pull lin the direction of the arrow M illustrated in Fig. l;and, when force is exerted, fthe pounds pull is indicated by the gauge156 having la movable pointer t8 and indicia 2t. This gauge It is of aweh-known commercial type and constitutes no part of the invention otherthan its Ainclusion .in the V.combination of elements vlierfeinafter tobe described.

The instrument broadly comprises a pair of slidably-interengaged`sections `designated .by 'the numerals 22 and 124., the former being.removably aiiixed to drawbar liiwhiie the .latter is connected to aportion of the work I2. lfthe pulling capacity of the tractor or machineattached to section 22 through drawbar lill is to Ibe vdeterminedwithout the use of a towed implement or load,vthe element l2 is anchoredand section 24 remains stationary while section '2li -is moved relative`thereto by .the pull of the tractor in the direction .of .arrow .l 4.

:Section :24 has a laterailyeiitendin'g portion or rabutment 26 inydirectly-oppcsed relation with Ia laterally-projected portion'cr head2t formed .on .section '22. rThe space .formed kbetween projections 2.6and .28 is designated by the numeral 39 and cocu-pied vby :cylinder .32and its contained plunger 34. This plungeris .siiiintable longitudinally`in ,cylinder 32,. and a portion of the said plungerprog'ects beyond theend of cylinder 311, as illustrated in Fig. 3. Thisprojected portion ofplunger'z34 is .protected by a dust skirt having one marginal edgeattached to cylinder 32, as at 3.8, while the Aopposite marginal edge issecured as at t0 to "the outern'iost end of l:plunger 34.

This skirt in tl'ie nature ci" a beliows; and, as relative movementbetween cylinder 32 .and 34 taires place, the skirt will fold to acccninodate the varying distances .between the endl f vof cylinder .32andthe outwardly-projecting end of plungerfl.y

Head 28r is provided with a bore 'i0 and an `internally-threaded socketr1.12, ythe latter receiving the threaded end of cylinder 32 oppositethat end Afrom which plunger 34 projects. Cylinder 32 is partially iledwith Huid 44, and it is this fluid 44 which constitutes themotivatingmedium for pointer I8 forming apart of :gauge It. Bore 40 isin communication with a conduit 46, and this conduit 46 connects withand supports gauge 3 I6. Fluid 44 is retained in that part of cylinder32 not occupied by plunger 34, bore 40 and conduit 46 by the innermostend of plunger 34 which is fortiiied by a seal 48 clearly illustrated insection in Fig. 3.

This seal is secured to the end of 4plunger 34 by a machine screw 50,and the cup-shape of seal 48 insures the retention of fluid 44. Lateralprojection or abutment 26 on section 24 is in the line of travel ofplunger 34 as sections 22 and 24 are relatively shifted longitudinally;and, as the space 30 between lateral projections 26 and 28 isdiminished, plunger 34 will -be forced into cylinder 32 to drive fluid44 into gauge I6 and actuate pointer I8 to indicate the amount of forcebeing exerted by the device or devices being tested.

Sections 22 and 24 are formed as clearly illustrated in Figs. 2, 4 and5, and section 24 has Ways 52 along each of its two longitudinal sidesto receive portions of section 22 as shown in Fig. 5. Head orlaterally-projecting member 28 on section 22 interconnects the portionsof section 22 which lie in these ways 52 provided in section 24, and thnportions of sections 22 which lie in these ways 52 are joined by tiemember 54, as illustrated in Figs. 2 and 3.

Ears B overlie head or laterally-projecting portion 28 of section 22 andare integral with section 24. Thus, the particular form and arrangementof the parts constituting sections 22 and 24 insure stableinterengagement during relative longitudinal sliding action, and thecompressing action exerted upon the cylinder and plunger assemblydisposed between elements 26 and 28 is deiinite and effective.

Such modifications as may fall within the scope of the appended claimsare contemplated and may be enjoyed without departing from the spirit ofthe invention.

Having thus described my invention, what is claimed as new and desiredto be secured by Letters Patent is:

l. A pounds pull tester of the character described comprising anelongated, longitudinally U-shaped section having means at one endthereof for attachment to a towing tractor or the like, and a laterallyextending portion at the opposite bight end thereof; anhydraulically-operated gauge mounted on said portion; a cylinder, havinga .partial filling of iiuid, carried by said portion and incommunication with the gauge; a plunger slidably disposed in thecylinder with a portion thereof extending beyond the cylinder; a secondsection having means at one end thereof for attachment to -a towedimplement or the like, said second section having a pair of opposed,longitudinally extending ways, the first-mentioned section havingelongated portions slidably disposed within said ways; and an abutmenton the second section at the opposite end thereof separate from theplunger and ypositioned to slide the plunger in the cylinder toward saidlaterally extending portion as the second section slides upon thefirst-mentioned section to move the gauge, the cylinder, and the plungertoward the abutment, and thereby force the plunger into engagement withthe abutment, the extended portion of said plunger having a closed,expansible, bellows skirt thereover, said skirt being formed to housethe extended portion of the plunger fas the length Varies due tomovement of the :plunger in the cylinder.

2. Combination pounds pull testing and linkage apparatus for pivotallyinterconnecting a tractor or the like having an elongated, normallyvertical pivot element adjacent the rear thereof and an implement or thelike having an elongated, normally vertical pivot member adjacent theforward end thereof and in longitudinal parallelism With said element,said apparatus comprising a nrst, elongated section having itslongitudinal axis normally disposed horizontally and provided with aU-shaped portion at one end thereof and a connector portion at theopposite end thereof, said U-shaped portion having a bight portionextending laterally of the first section at said one end of the latterand a pair of elongated, spacedl parallel leg portions extending in anormally horizontal direction from the bight portion to the connectorportion, said bight portion having a normally uppermost surface and aface between the zone of juncture of the leg portions with the bightportion, there being an elongated passage extending through the bightportion and communicating with said surface and said face thereof, saidconnector portion having a normally vertical bore therethrough adaptedfor pivotally receiving said element; an hydraulically operated pressuregauge mounted on said surface of the bight portion in communication withone end of said passage; an elongated cylinder having a partial fillingof duid, mounted on said face of the bight portion in communication withthe other end of said passage and extending horizontally from said facebetween and in parallelism with the leg portions; an elongated plungerslidably disposed in the cylinder with a length of said plunger adjacentone'end thereof extending beyond the cylinder at the end of the latterremote from said face of the bight portion; a second, elongated sectionhaving its longitudinal axis normally disposed horizontally and providedwith a track presenting portion at one end thereof and a coupler portionat the opposite end thereof, said track presenting portion beingprovided with a pair of opposed, longitudinally extending ways slidablyreceiving the leg portions of the U-shaped portion of said firstsection, said track presenting portion being provided at said one end ofthe second section with an upstanding abutment dismsed to engage saidone end of the plunger for sliding the plunger in the cylinder in adirection toward said face of the head as the first section carrying thecylinder and the gauge slides in the ways of the second section in adirection decreasing the distance between the face of the bight portionof said first section and the abutment on said second section, saidcoupler portion being provided with a normally vertical boretherethrough adapted for pivotally receiving said member; and a closed,expansible, bellows skirt mounted upon the cylinder in coveringrelationship to the extended length of the plunger for housing thelatter as the longitudinal dimension thereof varies due to movement ofthe plunger in the cylinder.

CALVIN Q. HEFNER.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 680,371 Brittan Aug. 13, 1901 1,361,990 Hatcher et al Dec. 14,1920 1,433,067 Burr Oct. 24, 1922

